The vascular effects are very complex and depend on the relative stimulation of the
various receptors

P1 receptors are located on endothelial cells and mediate a vasodilatation response

P2Y receptors are located on endothelial cells and mediate a vasodilatation response

P2X receptors are located on vascular smooth muscle cells and mediate vasoconstriction

50-350 mg/kg/min of ATP or adenosine significantly reduce
blood pressure (30-40%) by decreasing systemic vascular resitance, with only a small
increase in heart rate. Tachyphylaxis and rebound hypertension were not observed

150-300 mg/kg/min of ATP and adenosine have been used to
control blood pressure during phaeochromocytoma surgery

30-50 mg/kg/min adenosine causes coronary vasodilatation
without affecting the systemic circulation. This has been used to decrease the
incidence of early coronary artery bypass graft occlusion.

When given intravenously at low doses ATP and adenosine are rapidly metabolised during
their passage through the lung. ATP binds to the P2Y receptor on the pulmonary
endothelial cells, activating the nitric oxide system.

5 to 20mg ATP (or 6-12mg adenosine) causes normalisation of heart rate during episodes
of supraventricular tachycardia. It can also be used as a diagnostic aid in wide QRS
complex tachycardias

ATP stimulates the release of potassium which induces an electric current and results in
depression of the SA node and slowing of the AV node. This electrophysiological
effect is mediated by A1 receptors

Infusions up to 140 mg/kg/min are used in combination with an
imaging technique for the detection of coronary artery disease